A.^ 


•* 


baaed  August  ;,  1914. 

U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY. 
L.O.  HOWARD,  Entomologist  and  Chief  op  Bureau. 

I     . 

THE  PINK  BOLL  WORM. 

Hv  W.  1).  Httnter, 
In  Charge  0/ Southern  Field  Crop  Insect  Investigations,  Bureau  0/ Entomology . 

INTRODUCTION. 

Considerable  attention  has  recently  been  attracted  to  the  pink  boll- 
worm (GelecMa  gossypiella  Saund.)  (fig.  1 )  on  account  of  the  possibility 
of  its  introduction  into  the  United  States.  This  statement  has  been 
prepared  to  make  available  such  general  information  as  has  been 
called  for  from  time  to  time  by  planters  and  manufacturers. 

As  is  well  known,  many  of  the  most  injurious  insect  pests  of  the 
United  States  have  been  imported  from  foreign  countries.  There 
seems  no  doubt  that 
the  |>ink  bollworm 
would  be  able  likewise 
to  establish  itself  if  it 
were  introduced.  It 
would  be  very  likely 
to  add  greatly  to 
the  damage  sustained 
by  the  cotton  crop 
of   this  country  from 

insects,  which  now  amounts  to  about  fifty  millions  of  dollars  per 
annum.  That  the  introduction  of  the  insect  is  easily  possible  is  due 
to  certain  features  of  its  life  history  which  will  be  described  later.  As 
a  matter  of  fact,  in  1912  a  shipment  of  500  pounds  of  Egyptian  cotton 
Beed  which  was  heavily  infested  by  the  pink  bollworm  reached 
Arizona.  On  account  of  the  effective  control  law  in  that  State  and 
the  watchfulness  of  Dr.  A.  W.  Morrill,  the  State  entomologist,  the 
whole  shipment  was  destroyed  by  fire.  Otherwise  it  is  extremely 
probable  that  a  new  and  very  destructive  cotton  insect  would  have 
been  introduced.     This  would   have  been   particularly  unfortunate 

Note.— This  circular  gives  information  about  an  insect  that  damages  cotton  crops  and  whose  impor- 
tation into  this  country  is  to  be  guarded  against.  It  is  of  especial  interest  to  both  cotton  growers  and 
manulacturers. 

51617'— 14 


Fig.  1.— Pink  bollworm  (Gelechla  gossypiella):  Full-grown  larva, 
lateral  view.    Much  enlarged.    (Original.) 


THE    I'INK   BOLLWOBM. 


in  Arizona,  on  account  of  the  comparative  freedom  of  the  cotton 
grown  there  from  insect  injury  and  the  definite  indication  that  the 
Stat.'  will  soon  be  able  to  produce  large  quantities  of  cotton  of  em 
rior  quality  which  can  not  be  grown  in  other  parts  of  the  count] 

On  j^y  i,   1913,  the  Federal  Horticultural  Board  promulgated 
quarantine  against  cotton  seed  from  all  foreign  countries,  with 
object  of  preventing  the  invasion  of  the  ;>ink  bollworm.     Since  this 
quarantine  has  been  in  effeel  several  shipments  of  cotton  seed  1 
been  intercepted.     All  wen-  found  t<>  be  infested  by  the  pink  boll- 
worm;  one  shipment,  which  was  to  he  forwarded  to  Arizona,  Bhowed 
an  infestation  of  20  per  cent. 

In  this  connection  it  may  be  stated  that  there  ifi  no  longer  any  need 
for  importing  cotton  seed  from  Egypt,  since  there  is  an  amplesupplyof 

well-selected    and 
cfimatized  seed  a\  ail- 
cT  able  in  Arizona. 

DISTRIBUTION. 

The  pink  bollworm 
was   described    oti 

nally  from  India  in 
1st;!.  Since  that  time 
it  has  been  found  more 
or  less  generally  wide- 
spread in  India,  I 

of  Egyptian  cotton  showing  typical  Injuries  made  by  the    j(m       gnrmftj       Straits 
ink  bollworm.     Much  enlarged.     (Origin  ' 

ttlementf  .  pt, 

British  East  Africa.  German  East  Africa,  Nigeria,  Sierra  Leone,  and 
the  Hawaiian  Ishuuls.  In  the  Hawaiian  Inlands  it  was  undoubtedly 
introduced  in  cotton  seed  from  India.  There  is  also  a  doubtful 
record  of  the  occurrence  of  the  species  in  Japan. 

The  question  has  been  raised  as  to  whether  the  pink  bollworm  is 
not  already  established  in  the  United  States.     Vm-  several  reasons  it 

seems  certain  that  this  is  not  the  case.  Since  the  boll  weevil  invaded 
the  country  planters  have  paid  very  especial  attention  to  the  in- 
found  on  the  cotton  plant.  Each  year  hundreds  of  specimens  mis- 
taken for  the  boll  weevil  are  sent  to  the  Department  of  Apiculture 
and  to  State  entomologists.  Since  the  pink  bollworm  might  easily 
be  mistaken  for  the  boll  weevil  by  planters  it  is  altogether  likely  that 
it  would  have  been  bmnd  if  it  were  established  at  any  point  in  the 

United    States.      Moreover,    the    chances    of    introduction    have    been 

small  until  recently,  because  the  Egyptian  crop  has  not  been  generally 

infested  until  within  the.  Last  few  years. 


Fig.  2. 


TIIK     I'INK     IIOI.I.WOKM. 


HOW  THE  INSECT  SPREADS. 

The  moth  which  is  the  parent  of  the  pink  bollworm  is  a  fragile 
insect  and,  can  fly  no  great  distance.  II'  the  spread  of  the  species 
depended  upon  the  flight  of  the  adult  its  dispersion  into  new  regions 
would  he  very  slow.  However,  the  fact  that  the  immature  stages  occur 
in  cotton  seed,  furnishes  a  ready  means  of  artificial  spread  over  great 
distances.  (Sec  fig.  2.)  In  Egypt  experiments  have  shown  that  the 
larvae  may  live  within  the  cotton  seed  for  as  long  as  seven  months. 
Tins  would  allow  the  insect  to  he  transported  to  the  most  remote 
quarters  of  the  earth.  It  is  altogether  likely  that  the  original  home 
of  the  species  was  in  Asia  and  that  various  parts  of  Africa  have 
become  infested  by  ship- 
ments of  seed  from  that 
country,  as  was  the  ease  in 
the  Hawaiian  Islands. 


OCCURRENCE  OF  INFESTED 
SEED  IN  BALED  COTTON. 


\             '~~s"       ^\ 

\^~<&?y%y/ 

% 

> 

Fig.  3.— The  cotton  belt  of  the  United  States,  from  which 
all  shipments  of  Egyptian  cotton  seed  are  excluded  by 
quarantine.    (Original.) 


During  the  course  of  the 
investigation  of  the  possible 
introduction  of  the  pink 
bollworm  into  the  United 
States  it  was  found  that  a 
considerable  number  of 
seeds  are  to  be  found  in  the 
bales  of  Egyptian  cotton.  It  appears  that  a  certain  number  of  seeds 
pass  around  the  ends  of  the  rollers  in  the  gins,  and  some  may  pass 
between  the  roller  and  the  knife  through  small  openings  due  to  wear. 
When  the  possibility  of  the  introduction  of  the  pink  bollworm,  in 
seeds  in  bales  of  lint,  came  to  attention  an  investigation  was  made  in 
certain  mills  in  New  England  and  the  South  where  Egyptian  cotton  is 
used.  The  picker  waste  from37baleswasohtained  and  examined  care- 
fully. The  number  of  seed  recovered  varied  from  27  to  600  per  bale,  the 
average  per  bale  being  215.  It  was  noticed  that  the  number  of  seed 
found  in  the  picker  waste  depended  upon  the  grade  of  the  cotton — 
the  lower  grades  having  many  more  seeds  than  the  better  ones. 

In  the  seed  recovered  from  the  picker  waste  of  37  bales  15  dead  pink 
bollworms  and  1  live  one  were  found.  The  great  majority  of  the  seed 
appeared  to  be  uninjured  by  the  compression  of  the  cotton.  Baled 
cotton  is  therefore  dangerous  and  the  danger,  of  course,  is  greatest 
in  the  case  of  mills  located  in  the  cotton  belt  where  cotton  fields  are 
frequently  in  close  proximity.     (See  fig.  3.) 


HIE    PINK    BOLLWORM. 


Il  the  findings  from  the  examination  of  the  .:7  bales  to  which 
reference  has  been  made  are  used  as  a  criterion  it  appears  that  over 
16,000  live  larvae  of  the  pink  bollworm  are  brought  to  the  United 
States  each  year  and  thai  _'!•'_'  are  sent  i<.  the  southern  mills. 


HOW    THE   INSECT  INJURES  THE  COTTON. 


Tl„ 


pink    bollworm  affects    the  production  of  cotton  in  Beveral 

ways.     First,   a  considerable   number  of  squares  and   bolls 

injured  thai  they  fall  to  the  ground.     Tn  cases  of  heavy  infestation 

50percen1  of  the  crop  may  be  destroyed  in  this  way.     However,  this 

does  not  end  w  ith  the  falling  off  of  a  certain  amount  of  the  fruit. 

A  single  lock  of  a  boll  may  be  infest 
In  Buch  a  case  the  remaining  locks  de- 
velop hut  the  boll  opens  prematurely, 
and  the  fiber  is  short  and  kinky.  Thus 
the  grade  of  the  cotton  produced  may 
be  affected  materially.  Moreover,  the 
work  of  the  inseel  I  tins  in  the 

fiber  which  also  reduce  the  value  of 
the  product.     This  is   not    of    gn 
importance    in     the     case     of     certain 
ptian     varieties    which     produce 
dark-colored  lint,  hut  in  thevariei 
producing  white  lint,  like  the  Ah;: 
and    the    American    upland    and    8 
Island   varieties,   this  form   of  injury 
would  be  important. 

A  further  form  of  injury  by  the  pink 
bollworm  i^  in  relation  to  the  seed. 
Considerable  attention  was  attracted  in  England  during  1913  to 
(he  low  yield  in  oil  from  the  Egyptian  seed  which  is  milled  in  large 
quantities  in  that  country.  Tt  was  found  that  the  lessened  amount 
of  oil  expressed  was  due  to  the  infestation  of  the  seeds  by  this  insect. 
While  the  mills  ordinarily  obtain  from  10  to  20  per  cent  of  oil,  the 
amount  obtained  in  1913  was  found  to  he  reduced  to  from  Hi  to  17 
per  cent .      Another  form  of  loss  due  to  the  attack  of  the  in-  : 1 1 s t 

the  seed  is  the  reduction  in  the  percentage  of  germination.  In  many 
cases  the  infestation  must  he  SO  high  that  at  least  double  the  usual 
quantity  of  cotton  seed  musl  he  planted  to  obtain  a  stand. 

The  total  amount  of  loss  produced  by  the  pink  hollworm  in  any 
community  does  not  seem  to  have  been  determined.  In  practically 
all  countries  where  the  pink  hollworm  occurs  it  is  associated  with 
other  species  of  insects  which  work  in  the  bolls  and  squares  of  the 
cotton  plant,  and  the  relative  damage  by  these  differenl  inso 


FlO.4—  Pink  bollworm:  Pupa,  ventraland  lat- 
eral views.    Much  enlarged.    (Original.) 


THE   PINK    BOLLWORM. 


not  !>e  estimated.     Wherever  the  pest  is  found,  however,  it  is  con 
sidered  to  be  an  insect  of  great  Importance.     Tn  Egypt  in  jDIo,  ac- 
cording to  Gough  and  Storey,'  the  pink  bollworm  did  more  dam 
than  all  other  cotton  pests  combined.     In  the   Hawaiian  Islands, 
where  the  pest  was  introduced  within  the  last  few  years,  it  has  spread 
rapidly  and  has  becomo  by  far  the  most  important  enemy  of  cotton. 

FOOD  PLANTS. 

It  is  quite  evident  from  the  accounts  given  by  different  writers 
that  all  varieties  of  cotton  are  attacked  by  the  pink  bollworm. 
Careful  experiments  conducted  in  India 
failed  to  reveal  even  the  slightest  indi- 
cations of  varietal  resistance  to  the  boll- 
worm. It  is  therefore  practically  certain 
that  if  introduced  into  this  country  it 
would  attack  the  Sea  Island  as  well  as 
all  of  the  upland  strains  of  American 
cotton. 

Occasionally  the  pink  bollworm  appears 
to  attack  other  plants.  In  the  Hawaiian 
Islands,  Fulla  way  reared  it  from  Thespesia 
populnea.  In  Egypt,  Dudgeon  2  records 
"til"  (a  species  of  Sesamia)  and  pome- 
granates as  occasional  food  plants. 

LIFE  HISTORY. 

The  eggs  of  the  moth  of  the  pink  boll- 
worm, which  hatch  in  about  10  days,  are 
deposited  singly  on  various  parts  of  the 
cotton  plant.  The  minute  larvae  feed  on 
the  leaf  surface  for  a  short  time  but  very 
soon  penetrate  to  the  interior  of  the  cot  ton 
bolls,  or  "squares."  The  insect  spends 
about  20  days  in  this  stage,  becoming  in  its 
mature  larval  form  (fig.  1)  about  half  an  inch  long.  The  general  color 
is  pink,  from  which  the  popular  name  is  derived.  In  this  stage  it 
feeds  largely  upon  the  seeds,  and  when  ready  to  transform  to  the 
pupa  occupies  the  hull  from  which  the  kernel  has  been  devoured.  In 
examining  Egyptian  cotton  received  in  this  country  the  larvae  were 
frequently  found  to  have  caused  two  seeds  to  adhere  closely  together. 
In  fact  it  seems  to  be  a  definite  habit  of  the  larva  in  the  last  stage  to 
form  a  cell  of  two  hulls.     This,  however,  does  not  seem  to  be  an  inva- 


FiG.  5. — Pink  bollworm:  Moth,  or 
adult,  dorsal  view.  Much  enlarged. 
(Original.) 


1  Methods  for  the  destruction  of  the  pink  bollworm  in  cotton  seed.    Ministry  of  cotton  culture,  Cairo,  1914, 

P.I- 
»  Agricultural  Journal  of  Egypt,  vol.  2,  pt.  2,  1913,  p.  4. 


G  THH    PESTS    BOLL.WOBM. 

riable  rule,  aa  pupa?  (fig.  4)  have  sometimes  bean  found  in  the  lint. 
The  pupal  stage  Laata  for  about  14  day-,  after  which  the  insect  <•  Images 
t<>  a  moth. 

DESCRIPTION 

The  moth  (fig.  5)  of  the  pink  bollworm  i^  about  three-fourths  of 
an  inch  iu  expanse,  and  the  general  color  grayish  brown  with  darker 
blotches.  On.-  of  the  characteristic  marking-  is  a  large  dark  i 
near  the  apex  of  the  forewings,  whereas  the  hind  wing-  are  of  a 
uniform  grayish  color,  [n  this  stage  the  inseel  lives  al  leasl  lOdi 
probably  considerably  longer,  and  begins  the  deposition  of  eggs  in 
three  or  four  days  after  it  emerges  from  the  chrysalis. 

o 


WARHI  vr.TKV  :  i."\  l!;\  \n:\  1    PI  rliK  :  1914 


UNIVERSITY  OF   FLORIDA 


3  1262  08929  0653 


